KR101639535B1 - Thermal energy recovery device - Google Patents

Abstract

The present invention provides a heat energy recovery device capable of suppressing occurrence of a water hammer phenomenon in a preheater.
A heat energy recovery device comprising: an evaporator (10) for evaporating a working medium by heat exchange between a gaseous heating medium and a working medium; a heating medium flowing out of the evaporator (10) and a working medium before being introduced into the evaporator An energy recovery unit 20 for recovering the expansion energy of the working medium flowing out of the evaporator 10 and sending the working medium to the preheater 12, a preheater 12, When the supercooling degree of the heating medium flowing into the preheater 12 is prohibited from flowing into the preheater 12 when the supercooling degree of the heating medium flowing into the preheater 12 is not greater than 0 degrees, And a control unit (40) for performing an operation of introducing the heating medium into the preheater (12).

Description

{THERMAL ENERGY RECOVERY DEVICE}

The present invention relates to a thermal energy recovery device.

BACKGROUND ART [0002] Heat energy recovery devices for recovering power from steam (gas phase heating medium) such as exhaust gas discharged from various facilities of a factory are known. For example, Patent Document 1 discloses an evaporator that includes an evaporator that heats a working medium by a gaseous heating medium supplied from an external heat source, a preheater that heats the working medium before flowing into the evaporator by a heating medium flowing out of the evaporator, A power generator connected to the screw expander; a condenser for condensing the working medium flowing out of the screw expander; and a pump for sending the working medium condensed in the condenser to the preheater, wherein the power generator is connected to the screw expander, (Heat energy recovery device) is disclosed. The preheater and the evaporator each have a working medium flow path through which the working medium flows and a heating medium flow path through which the heating medium flows.

Japanese Unexamined Patent Publication No. 2111591

In the heat energy recovery apparatus described in Patent Document 1, the heating medium flowing out of the evaporator flows into the preheater in any one of a gas phase, a liquid phase, or a gas-liquid two phase. In this case, it is known that a so-called water hammer phenomenon may occur in the preheater. It is presumed that this water hammer phenomenon mainly occurs by the following principle.

When the gaseous heating medium (steam or hot gas) flows into the heating medium flow path of the preheater, the heating medium is cooled by the liquid (drain or mist) in the heating medium flow path, and is condensed to sharply decrease in volume. Then, a relatively low pressure region is generated in the heating medium flow path. As a result, the liquid in the heating medium flow path moves toward the relatively low pressure region, so that the liquid collides with the inner surface of the heating medium flow path.

An object of the present invention is to provide a heat energy recovery device capable of suppressing occurrence of a water hammer phenomenon in a preheater.

As a means for solving the above-mentioned problems, the present invention provides an evaporator, comprising: an evaporator for evaporating the working medium by heat exchange with a gaseous heating medium supplied from the outside; a heating medium flowing out of the evaporator; An energy recovery unit that recovers the expansion energy of the working medium flowing out of the evaporator and sends the working medium to the preheater; and a supercooling degree of the heating medium flowing into the preheater, When the degree of supercooling of the heating medium flowing into the preheater is greater than 0 degrees, the operation of flowing the heating medium into the preheater The heat energy recovery device comprising:

In this heat energy recovery apparatus, the heat energy obtained by the working medium in the preheater and the evaporator can be recovered by the energy recovery unit, and the occurrence of the water hammer phenomenon in the preheater can be suppressed. Specifically, when the supercooling degree of the heating medium flowing into the preheater is not greater than 0 degrees (when there is a gaseous heating medium), the heating medium is prevented from flowing into the preheater, and when the supercooling degree is larger than 0 The heating medium flows into the preheater. That is, a liquid heating medium flows into the preheater. Therefore, the occurrence of the water hammer phenomenon in the preheater is suppressed. More specifically, occurrence of a water hammer phenomenon caused by condensation in the preheater after the gaseous heating medium is introduced into the preheater is suppressed.

In this case, when the supercooling degree of the heating medium flowing into the preheater is greater than 0 degrees and the supercooling degree of the heating medium flowing out of the evaporator is not less than a specific lower limit value, the control unit controls the heating medium to flow into the preheater The degree of supercooling of the heating medium flowing into the preheater is not greater than 0 degrees or the supercooling degree of the heating medium flowing out from the evaporator is less than the lower limit value even if the supercooling degree is greater than 0 degree, It is preferable to perform an operation for prohibiting the inflow to the preheater.

In this way, the occurrence of the water hammer phenomenon in the preheater is suppressed, and the occurrence of the water hammer phenomenon in the evaporator is also suppressed. Specifically, when the supercooling degree of the heating medium flowing out of the evaporator is less than the lower limit value, the heating medium may be in a state of vapor-liquid two phase, for example. In this case, when the heating medium flows into the preheater, since the pressure loss occurs in the preheater, the heating medium becomes difficult to pass through the preheater. As a result, the heat exchange efficiency in the preheater is lowered, and the pressure loss becomes the cause (resistance), making it difficult for the liquid heating medium (drain) to flow out from the evaporator. When the gaseous heating medium flows into the evaporator in this state, the gaseous heating medium is cooled in the drain, and the volume of the gaseous heating medium suddenly decreases, which may cause a water hammer phenomenon in the evaporator. On the other hand, in the present energy recovery apparatus, when the supercooling degree of the heating medium flowing out of the evaporator is less than the lower limit value, the introduction of the heating medium into the preheater is prohibited so that the decrease in heat exchange efficiency in the preheater is suppressed, (The drainage of the liquid heating medium is promoted) is suppressed, so that the occurrence of the water hammer phenomenon in the evaporator is suppressed.

In the present invention, when the supercooling degree of the heating medium flowing into the preheater is greater than 0 degrees and the supercooling degree of the heating medium flowing out of the evaporator is not more than a specific upper limit value, When the supercooling degree of the heating medium flowing into the preheater is not greater than 0 degrees or the supercooling degree of the heating medium flowing out of the evaporator is larger than the upper limit value even if the supercooling degree is larger than 0 degree, It is preferable to perform an operation of discharging the medium to the outside without flowing the medium into the preheater.

In this way, the occurrence of the water hammer phenomenon in the preheater is suppressed, the outflow of the liquid heating medium (drain) from the evaporator is promoted, and the occurrence of the water hammer phenomenon in the evaporator is suppressed. Specifically, when the supercooling degree of the heating medium flowing out of the evaporator is larger (too high) than the upper limit value, a considerably liquid heating medium (drain) is stored in the vicinity of the outlet of the flow path through which the heating medium flows in the evaporator . When the gaseous heating medium flows into the evaporator in this state, the gaseous heating medium is cooled in the drain, and the volume of the gaseous heating medium suddenly decreases, which may cause a water hammer phenomenon in the evaporator. On the other hand, when the liquid heating medium flows into the preheater in this state, since the liquid heating medium requires time to pass through the preheater, the liquid heating medium (drain) is difficult to flow out from the evaporator . On the other hand, in the present energy recovery apparatus, when the supercooling degree of the heating medium flowing out of the evaporator is larger than the upper limit value (in the evaporator, when the sensible heat is sufficiently recovered as well as the latent heat of the heating medium by the working medium) By discharging the liquid to the outside without flowing into the preheater, the time required for the liquid heating medium to be discharged from the evaporator to the outside is shortened, so that the drainage of the drain from the evaporator is promoted. Therefore, occurrence of the water hammer phenomenon in the evaporator is suppressed.

In the present invention, when the supercooling degree of the heating medium flowing into the preheater is greater than 0 degrees and the supercooling degree of the working medium flowing into the evaporator is greater than 0 degrees, When the supercooling degree of the heating medium flowing into the preheater is not greater than 0 degree or the supercooling degree of the working medium flowing into the evaporator is not greater than 0 degree even if the supercooling degree is larger than 0 degree It is preferable to perform an operation for prohibiting the inflow of the heating medium into the preheater.

In this way, the occurrence of the water hammer phenomenon in the preheater is suppressed, and the drift of the working medium in the evaporator is suppressed, so that the heat exchange efficiency in the evaporator, that is, the energy recovery efficiency of the energy recovery section is improved. For example, when the gas-liquid two-phase working medium flows into the evaporator, the specific gravity of the gaseous working medium and the specific gravity of the liquid working medium are different from each other. An area through which the medium passes is formed. As a result, in the evaporator, it is feared that uniform heat exchange between the working medium and the heating medium is not performed (heat exchange efficiency is lowered). On the other hand, in the present energy recovery apparatus, when the supercooling degree of the working medium flowing into the evaporator is not greater than 0 degree (when there is a working medium in the vapor phase), inflow of the heating medium into the preheater is prohibited , The heating of the working medium by the heating medium in the preheater is stopped, so that the working medium flowing out of the preheater is prevented from being contained in the working medium in the vapor phase. Therefore, the drift of the working medium in the evaporator is suppressed.

Further, in the present invention, it is preferable that, when the predetermined stop condition is satisfied, the control unit performs an operation of discharging the heating medium to the outside without flowing the heating medium into the preheater.

By doing so, the outflow of the liquid heating medium (drain) from the evaporator at the time of stopping is promoted, so that the occurrence of the water hammer phenomenon in the evaporator at the time of starting the heat energy recovery apparatus is suppressed. Specifically, when the stop condition is satisfied (when the apparatus is stopped), since the heating medium is discharged to the outside without flowing into the preheater, the pressure loss in the preheater is not generated, so that the drainage of the drain from the evaporator is promoted do. Therefore, the occurrence of the water hammer phenomenon in the evaporator at the time of starting the apparatus is suppressed.

Further, in the present invention, it is preferable to further include a connection flow passage for connecting the pre-heater and the evaporator, and the connection flow passage preferably has a shape extending in a straight line.

In this case, since the pressure loss generated in the connection passage is reduced, when oil is contained in the working medium, the staying of the oil in the connection passage is suppressed. Thereby, an appropriate amount of oil flows into the energy recovery section.

As described above, according to the present invention, it is possible to provide a heat energy recovery device capable of suppressing the occurrence of a water hammer phenomenon in a preheater.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view schematically showing a configuration of a heat energy recovery apparatus according to an embodiment of the present invention; Fig.
2 is a flow chart showing the control contents of the control unit at the time of start and normal operation.
3 is a flowchart showing control contents of the control section at the time of stop.

A heat energy recovery device according to an embodiment of the present invention will be described with reference to Figs. 1 to 3. Fig.

1, the heat energy recovery apparatus includes an evaporator 10, a preheater 12, an energy recovery unit 20, a heating medium supply passage 30, and a control unit 40 have.

The evaporator 10 evaporates the working medium by exchanging heat between the gaseous heating medium (exhaust gas of the factory, etc.) supplied from the outside and the working medium (such as HFC245fa). The evaporator 10 has a working medium flow path 10a through which the working medium flows and a heating medium flow path 10b through which the heating medium flows. In the present embodiment, a plate type heat exchanger is used as the evaporator 10. However, a so-called shell and tube heat exchanger may be used as the evaporator 10.

The preheater 12 heats the working medium by exchanging heat between the heating medium flowing out of the evaporator 10 and the working medium before being introduced into the evaporator 10. The preheater 12 has a working medium flow path 12a through which the working medium flows and a heating medium flow path 12b through which the heating medium flows. In the present embodiment, a plate-type heat exchanger is also used as the pre-heater 12. However, the so-called shell and tube heat exchanger may be used as the pre-heater 12 as in the case of the evaporator 10. The height position of the upstream end of the heating medium flow path 12b of the preheater 12 is set to be equal to or lower than the height position of the downstream end of the heating medium flow path 10b of the evaporator 10. [ The height position of the downstream end of the working medium flow path 12a of the preheater 12 is set to be equal to the height position of the upstream end of the working medium flow path 10a of the evaporator 10. [ The downstream end of the working medium flow path 12a of the preheater 12 and the upstream end of the working medium flow path 10a of the evaporator 10 are connected by the connecting flow path 29. [ In the present embodiment, the connection passage 29 has a shape extending straightly without having a bent portion.

The energy recovery unit 20 includes an expansion unit 22, a power recovery unit 23, a condenser 24, a pump 26, and a recovery flow path 28.

The return flow passage 28 is connected to the evaporator 10 and the inflator 22, between the inflator 22 and the condenser 24, between the condenser 24 and the pump 26, (12). That is, the working fluid passes through the evaporator 10, the inflator 22, the condenser 24, the pump 26 and the preheater 12 in this order by the recovery flow path 28 and the connection flow path 29 A circulating circuit circulating in order to form a circulating loop. In the present embodiment, oil circulates together with the working medium through the closed circuit.

The inflator 22 is provided on the downstream side of the evaporator 10 in the recovery flow path 28. The inflator 22 expands the gaseous working medium flowing out of the evaporator 10. In this embodiment, as the inflator 22, a positive displacement screw expander having a rotor rotationally driven by the expansion energy of the gaseous working medium flowing out of the evaporator 10 is used. Specifically, the inflator 22 has a pair of screw rotors.

The power recovery device 23 is connected to the inflator 22. In the present embodiment, a generator is used as the power recovery device 23. The power recovery device 23 has a rotation shaft connected to one of the pair of screw rotors of the inflator 22. The power recovery device 23 generates electric power by rotating the rotation shaft in accordance with the rotation of the screw rotor. As the power recovery device 23, a compressor or the like other than the generator may be used.

The condenser 24 is provided on the downstream side of the inflator 22 in the recovery flow path 28. The condenser 24 condenses (liquefies) the working medium flowing out of the inflator 22 by cooling it with a cooling medium (cooling water or the like) supplied from the outside.

The pump 26 is provided on the downstream side of the condenser 24 in the recovery flow path 28. The pump 26 pressurizes the liquid working medium to a predetermined pressure and sends it to the preheater 12. As the pump 26, a centrifugal pump having an impeller as a rotor, a gear pump including a pair of gears, a screw pump, a trochoid pump, and the like are used.

The heating medium supply passage 30 is a flow passage for supplying the heating medium from the external heat source for generating the gaseous heating medium to the evaporator 10 and the preheater 12 in this order. The heating medium supply passage 30 is configured to be connectable to the heating medium passage 10b of the evaporator 10 and is configured to be connectable to the heating medium passage 12b of the pre-

In this embodiment, a drain tank 32 and a steam trap 34 are provided in a portion between the evaporator 10 and the preheater 12 in the heating medium supply passage 30. The drain tank 32 stores a liquid heating medium in the heating medium flowing out from the evaporator 10. The steam trap 34 prohibits the passage of the gaseous heating medium out of the heating medium flowing out of the drain tank 32 and permits the passage of the heating medium in the liquid phase.

A bypass flow path 36 for bypassing the preheater 12 is connected to the heating medium supply flow path 30. Specifically, the upstream end of the bypass passage 36 is connected to a portion of the heating medium supply passage 30 between the steam trap 34 and the preheater 12, and the downstream end of the bypass passage 36 The end portion is connected to a portion of the heating medium supply passage 30 located downstream of the preheater 12.

A first discharge flow path 38 and a second discharge flow path 39 are connected to the heating medium supply flow path 30. The first discharge flow passage 38 is a flow passage for discharging the heating medium flowing out from the drain tank 32 to the outside and a portion between the drain tank 32 and the steam trap 34 in the heating medium supply passage 30 Respectively. The second discharge flow path 39 is a flow path for discharging the heating medium before being introduced into the evaporator 10 to the outside and connected to a portion on the upstream side of the evaporator 10 in the heating medium supply flow path 30.

The bypass flow path 36 is provided with a first opening / closing valve V1. A portion of the heating medium supply passage 30 downstream of the connecting portion between the heating medium supply passage 30 and the bypass passage 36 and upstream of the preheater 12 is provided with a second opening / Respectively. A third open / close valve V3 (not shown) is provided in the heating medium supply passage 30 on the downstream side of the preheater 12 and upstream of the connecting portion between the heating medium supply passage 30 and the downstream side end portion of the bypass passage 36 Is installed. A fourth opening / closing valve V4 is provided in the first discharge flow passage 38. [ A fifth open / close valve V5 is provided in the second discharge flow passage 39. [ The sixth opening / closing valve V6 is provided in a portion of the heating medium supply passage 30 upstream of the connection portion between the heating medium supply passage 30 and the second discharge passage 39. [ In the present embodiment, electromagnetic valves capable of switching between an open state and a closed state are used as the open / close valves V1 to V6.

The control unit 40 performs a switching operation for switching the opening and closing of the opening / closing valves V1 to V6 in accordance with a predetermined condition. Whether or not the supercooling degree? 1 of the heating medium flowing into the preheater 12 is larger than 0 degrees and whether the supercooling degree? 2 of the heating medium flowing out of the evaporator 10 is within a predetermined range is determined from the preheater 12 Whether or not the supercooling degree β of the outgoing working medium is greater than 0 ° and whether the pressure P of the gaseous heating medium flowing into the evaporator 10 is less than the predetermined value P0. The supercooling degree? 1 is determined by a temperature sensor 41 and a pressure sensor 42 provided in a portion of the heating medium supply passage 30 upstream of the preheater 12 (a region between the preheater 12 and the second opening / closing valve V2) As shown in FIG. The supercooling degree? 2 is determined by the temperature sensor 43 and the pressure sensor 44 provided in the portion of the heating medium supply passage 30 downstream of the evaporator 10 (the region between the evaporator 10 and the drain tank 32) ). ≪ / RTI > The supercooling degree? Is derived from the detected values of the temperature sensor 45 and the pressure sensor 46 provided in the connection passage 29. Here, the subcooling degree refers to a temperature drop from the saturation temperature (condensation temperature). Specifically, "supercooling degree = saturation temperature (condensation temperature) - temperature of heating medium or working medium" is calculated. That is, the term "supercooling degree of 0 degrees" means that the temperature of the heating medium or the working medium is equal to the saturation temperature (condensation temperature). The pressure P is applied to a pressure sensor 47 provided at a portion of the heating medium supply passage 30 upstream of the evaporator 10 (a portion between the evaporator 10 and the upstream end of the second discharge passage 39) ). The control unit 40 performs the switching operation while performing an operation of adjusting the rotational speed of the pump 26 so that the degree of superheat of the working medium flowing out of the evaporator 10 is received within a predetermined range.

Next, with reference to Fig. 2, specific control contents of the control unit 40 at the time of start-up and normal operation will be described. The first on-off valve V1 is in the open state, the second on-off valve V2 and the third on-off valve V3 are in the closed state, and the fourth on-off valve V4 and the fifth on- And the sixth on-off valve V6 is in the closed state.

When the operation of the apparatus is started (step S10), the controller 40 sets the first on-off valve V1 to the open state, the second on-off valve V2 and the third on-off valve V3 to the closed state, The valve V5 is closed, and the sixth opening / closing valve V6 is opened (step S11). Thus, the heating medium is discharged to the outside through the bypass flow path 36 without passing through the evaporator 10 and then into the preheater 12. [ Further, by the start of operation, supply of the cooling medium to the condenser 24 and driving of the pump 26 are also started. As a result, the working medium circulates in the closed circuit, so that the power (power in the present embodiment) is recovered by the power recovery device 23.

Subsequently, the control unit 40 judges whether or not the supercooling degree? 2 of the heating medium flowing out of the evaporator 10 is not less than the specified lower limit value a but not more than the specified upper limit value b (step S12). If the supercooling degree? 2 is smaller than the lower limit value a or larger than the upper limit value b (NO in step S12), the control unit 40 returns to step S12, that is, (Hereinafter, referred to as " bypass state ") in which the gas is discharged to the outside through the flow path 36.

The reason why the bypass state is maintained when the supercooling degree? 2 is greater than (not too high) the upper limit value b is to suppress the occurrence of the water hammer phenomenon in the evaporator 10. Specifically, when the apparatus is started, the temperature of the evaporator 10 is lower than that at the time of normal operation. Therefore, the heating medium flowing into the evaporator 10 is easily condensed, (Drain) of the heater is liable to be stored. When the drain is stored in the heating medium flow path 10b, the supercooling degree? 2 flowing out from the heating medium flow path 10b is increased. In other words, when the supercooling degree? 2 is high (larger than the upper limit value b), it is considered that the drain is considerably stored in the heating medium flow path 10b. When the gaseous heating medium flows into the evaporator 10 in this state, the volume of the gaseous heating medium suddenly decreases due to the cooling of the gaseous heating medium, thereby possibly causing a water hammer phenomenon in the evaporator 10. On the other hand, in this state, when the liquid heating medium flows into the pre-heater 12, it takes time for the liquid heating medium to pass through the heating medium flow path 12b of the pre-heater 12, The liquid heating medium (drain) becomes difficult to flow out from the inside. Therefore, when the supercooling degree? 2 is larger than the upper limit value b, the bypass state is maintained, so that the time required until the liquid heating medium is discharged to the outside from the evaporator 10 is shortened. Drainage of the drain is promoted. Therefore, occurrence of the water hammer phenomenon in the evaporator 10 is suppressed.

On the contrary, the reason why the bypass state is maintained when the supercooling degree? 2 is less than the lower limit value a is mainly because the lowering of the heat exchange efficiency in the preheater 12 is suppressed and the occurrence of the water hammer phenomenon in the evaporator 10 . Specifically, when the supercooling degree? 2 is less than the lower limit value a, the heating medium may be in a state of vapor-liquid two phase, for example. In this case, when the heating medium flows into the pre-heater 12, since the pressure loss occurs in the pre-heater 12, the heating medium becomes difficult to pass through the pre-heater 12. As a result, the heat exchange efficiency in the preheater 12 is lowered. Further, the pressure loss becomes the cause (resistance), and the liquid heating medium (drain) is hard to flow out from the evaporator 10. Therefore, when the supercooling degree? 2 is less than the lower limit value a, the bypass state is maintained, that is, the inflow of the heating medium into the preheater 12 is inhibited, whereby the lowering of the heat exchange efficiency in the preheater 12 is suppressed, It is possible to prevent a state in which the liquid heating medium (drain) is difficult to flow out from the inside of the evaporator 10 due to the pressure loss (because the outflow of the liquid heating medium is promoted) Generation is suppressed.

In this case, since the heat recovery by the working medium in the preheater 12 is not performed, the low-temperature working medium flows out of the preheater 12 compared with the case where the heating medium flows into the preheater 12, ≪ / RTI > Thereby, the heating medium in the evaporator 10 is sufficiently cooled by the working medium. Since the heating medium is prevented from flowing into the preheater 12 until the supercooling degree α2 of the heating medium flowing out of the evaporator 10 becomes the lower limit value a or more, a state in which the heat exchange efficiency in the evaporator 10 is lowered .

When the supercooling degree? 2 is equal to or greater than the lower limit value a and equal to or smaller than the upper limit value b (YES in step S12), the control unit 40 determines whether or not the supercooling degree? Of the working medium flowing into the evaporator 10 is greater than 0 (Step S13). As a result, if the supercooling degree? Is not larger than 0 degree ("NO" in step S13), the control section 40 returns to step S12 again, that is, maintains the bypass state.

The reason why the bypass state is maintained when the supercooling degree? Is not larger than 0 degree is to improve the heat exchange efficiency in the evaporator 10, that is, the energy recovery efficiency of the energy recovery unit 20. [ For example, when the gas-liquid two-phase working medium flows into the evaporator 10, the specific gravity of the gaseous working medium and the specific gravity of the liquid working medium are different from each other. Therefore, in the working medium flow path 10a of the evaporator 10 , A region through which the gaseous working medium passes and a region through which the liquid working medium passes are formed. As a result, it is feared that uniform heat exchange between the working medium and the heating medium is not performed in the evaporator 10 (heat exchange efficiency is lowered). Therefore, when the supercooling degree? Is not larger than 0 degree (in the case where a gaseous working medium may exist), the bypass state is maintained, that is, the heating medium is prevented from flowing into the preheater 12. As a result, since the heating of the working medium by the heating medium in the preheater 12 is stopped, the working medium flowing out of the preheater 12 is inhibited from being contained in the working medium in the vapor phase. Therefore, the drift of the working medium in the evaporator 10 is suppressed, and the heat exchange efficiency in the evaporator 10 is improved.

When the supercooling degree? Is larger than 0 degrees (YES in step S13), the control unit 40 sets the first on-off valve V1 to the closed state, the second on-off valve V2 and the third on-off valve V3 to the open state, The fourth opening / closing valve V4 and the fifth opening / closing valve V5 are closed, and the sixth opening / closing valve V6 is opened (step S14). Thereby, the heating medium passes through the evaporator 10, passes through the preheater 12, and is then discharged to the outside. That is, the heat energy recovery device is in the normal operation state.

Subsequently, the control unit 40 determines whether or not the supercooling degree? 1 of the heating medium flowing into the preheater 12 is greater than zero degrees (step S15). As a result, when the supercooling degree? 1 is not larger than 0 degree ("NO" in step S15), the control section 40 returns to step S11 and returns to the bypass state.

The reason for setting the bypass state when the supercooling degree? 1 is not larger than 0 degrees is to suppress the occurrence of the water hammer phenomenon in the preheater 12. Specifically, when the supercooling degree? 1 is not larger than 0 degree (when there is a gaseous heating medium), if the heating medium flows into the preheater 12, the gaseous heating medium flows into the preheater 12 Water hammer phenomenon may occur due to condensation in the preheater 12. Therefore, when the supercooling degree? 1 is not larger than 0 degree, the bypass state is maintained, that is, the inflow of the heating medium into the preheater 12 is prohibited. As a result, the occurrence of the water hammer phenomenon in the preheater 12 is suppressed.

On the other hand, if the supercooling degree? 1 is larger than zero degrees (YES in step S15), the control unit 40 determines whether the supercooling degree? 2 is equal to or more than the lower limit value a and equal to or less than the upper limit value b (step S16). As a result, when the supercooling degree? 2 is smaller than the lower limit value a or larger than the upper limit value b ("NO" in step S16), the control section 40 returns to step S11 and returns to the bypass state. The reason is as described above. In addition, when the supercooling degree? 2 is lower than the lower limit value a, the state of returning to the bypass state prevents the heat exchange efficiency of the evaporator 10 from being lowered, and suppresses the occurrence of the water hammer phenomenon in the preheater 12 do.

If the supercooling degree? 2 is equal to or greater than the lower limit value a and equal to or smaller than the upper limit value b (YES in step S16), the control unit 40 determines whether or not the supercooling degree? Of the working medium flowing into the evaporator 10 is greater than 0 (Step S17). As a result, when the supercooling degree? Is not larger than 0 degree ("NO" in step S17), the control section 40 returns to step S11 and returns to the bypass state. The reason is as described above.

On the other hand, if the supercooling degree? Is larger than zero degrees (YES in step S17), the control section 40 returns to step S15, that is, continues the normal operation state.

Next, specific control contents of the control unit 40 at the time of stop will be described with reference to Fig.

When the control unit 40 receives the stop signal (step S20), the control unit 40 stops the supply of the heating medium to the evaporator 10 and the preheater 12 and opens the first opening / closing valve V1 The second open / close valve V2 and the third open / close valve V3 are closed, the fourth open / close valve V4 and the fifth open / close valve V5 are closed, and the sixth open / close valve V6 is closed (step S21).

Thereafter, the control unit 40 stops the pump 26 (step S22). At the same time as or before or after the stop of the pump 26, the supply of the cooling medium to the condenser 24 is also stopped.

Subsequently, the control unit 40 determines whether the pressure P of the gaseous heating medium flowing into the evaporator 10 is less than the predetermined value P0 (step S23). In the present embodiment, this condition is referred to as a " stop condition ".

If the pressure P is equal to or larger than the predetermined value P0 (NO in step S23), that is, if the stop condition is not established, the control section 40 returns to step S23.

On the other hand, if the pressure P is less than the predetermined value P0 (YES in step S23), the control unit 40 sets the first on-off valve V1 to the open state, the second on-off valve V2 and the third on- The fourth opening / closing valve V4 and the fifth opening / closing valve V5 are opened and the sixth opening / closing valve V6 is closed (step S24). The reason for this is to promote the discharge of the heating medium in the heating medium flow path 10b of the evaporator 10 to the outside. Specifically, the heating medium supply passage 30 is opened to the outside by opening the fourth opening / closing valve V4 and the fifth opening / closing valve V5, so that the heating medium in the heating medium passage 10b of the evaporator 10 .

As described above, in the present thermal energy recovery apparatus, while the heat energy obtained by the working medium in the evaporator 10 and the preheater 12 is recovered by the energy recovery unit 20, the water hammer phenomenon Can be suppressed. Specifically, when the supercooling degree α1 of the heating medium flowing into the preheater 12 is not greater than 0 degrees (when there is a gaseous heating medium), inflow of the heating medium into the preheater 12 is prohibited, When? 1 is larger than 0 degree, the inflow of the heating medium into the preheater 12 is allowed. That is, the preheater 12 is supplied with a liquid heating medium. Therefore, the occurrence of the water hammer phenomenon in the preheater 12 is suppressed. More specifically, occurrence of a water hammer phenomenon caused by condensation in the preheater 12 after the gaseous heating medium is introduced into the preheater 12 is suppressed.

In the present embodiment, the latent heat of the heating medium is all recovered by the working medium in the evaporator 10, so that the heat exchange efficiency in the evaporator 10, that is, the energy recovery efficiency of the energy recovery unit 20 is improved . Specifically, in this energy recovery apparatus, when the supercooling degree? 2 of the heating medium flowing out of the evaporator 10 is lower than the lower limit value a, the inflow of the heating medium into the preheater 12 is prohibited. As a result, since the heat medium is not recovered by the working medium in the pre-heater 12, the low-temperature working medium flows out of the pre-heater 12 as compared with the case where the heating medium flows into the pre- heater 12, ≪ / RTI > As a result, the heating medium in the evaporator 10 is sufficiently cooled by the working medium. Since the heating medium is prevented from flowing into the preheater 12 until the supercooling degree? 2 of the heating medium flowing out of the evaporator 10 becomes the lower limit value a or more, the occurrence of the water hammer phenomenon in the preheater 12 Both of the state where the heat exchange efficiency in the evaporator 10 is lowered are prevented. In addition, since a state in which the liquid heating medium (drain) is difficult to flow out from the evaporator 10 due to the pressure loss when the heating medium passes through the preheater 12 is prevented, the water hammer The occurrence of the phenomenon is also suppressed.

In addition, in the present embodiment, the outflow of the liquid heating medium (drain) from the evaporator 10 is promoted at the start-up time and the normal operation of the present thermal energy recovery apparatus, so that the water hammer phenomenon The occurrence is further suppressed. Specifically, in this energy recovery apparatus, when the supercooling degree? 2 of the heating medium flowing out of the evaporator 10 is larger than the upper limit value b (the evaporator 10 is capable of sufficiently recovering sensible heat as well as latent heat of the heating medium by the working medium The heating medium is discharged to the outside without flowing the heating medium into the preheater 12. [ This shortens the time required for the liquid heating medium to be discharged from the evaporator 10 to the outside, thereby facilitating the drainage of the drain from the evaporator 10. Therefore, the occurrence of the water hammer phenomenon in the evaporator 10 during start-up and normal operation is suppressed.

In this embodiment, the operation for promoting the outflow of the liquid heating medium from the evaporator 10 at the time of stopping the thermal energy recovery apparatus (the heating medium is discharged to the outside without flowing into the preheater 12 Operation of the evaporator 10 is performed, the occurrence of the water hammer phenomenon in the evaporator 10 at the start-up of the present apparatus is further suppressed.

Further, in this embodiment, since the drift of the working medium in the evaporator 10 is suppressed, the heat exchange efficiency in the evaporator 10 is further improved. Specifically, in this energy recovery apparatus, when the supercooling degree β of the working medium flowing into the evaporator 10 is not greater than 0 ° (in the case where a gaseous working medium may exist), the inflow of the heating medium into the preheater 12 The heating of the working medium by the heating medium in the preheater 12 is stopped so that the working medium flowing out of the preheater 12 is inhibited from being contained in the vaporous working medium. Therefore, the drift of the working medium in the evaporator 10 is suppressed, and the heat exchange efficiency in the evaporator 10 is improved.

Further, since the connection passage 29 has a shape extending straight, the pressure loss generated in the connection passage 29 is reduced. As a result, the oil contained in the working medium is prevented from staying in the connection passage 29. Therefore, an appropriate amount of oil flows into the inflator 22 of the energy recovery unit 20. [

It is also to be understood that the embodiments disclosed herein are illustrative and non-restrictive in all respects. The scope of the present invention is defined by the appended claims rather than by the foregoing description of the embodiments, and includes all modifications within the meaning and scope equivalent to those of the claims.

For example, when the supercooling degree? 2 of the heating medium flowing out of the evaporator 10 is larger than the upper limit value b, the control unit 40 may open the fourth opening / closing valve V4. This allows the heating medium in the liquid phase to flow through the first discharge flow path 38 to the outside of the steam trap 34 in the case where the liquid heating medium is discharged to the outside through the bypass flow path 36 after passing through the steam trap 34. [ And is smoothly discharged to the outside.

Therefore, the discharge of the liquid heating medium (drain) from the heating medium flow path 10b of the evaporator 10 is promoted, so that occurrence of the water hammer phenomenon in the evaporator 10 is further suppressed.

10: Evaporator
12: Preheater
20: Energy recovery unit
29: Connection channel
30: heating medium supply flow path
32: Drain tank
34: Steam Trap
36: Bypass flow
38:
39: second exhaust channel
40:
V1: First open / close valve
V2: Second open / close valve
V3: Third open / close valve
V4: Fourth opening valve
V5: The fifth opening / closing valve
V6: Sixth open-close valve

Claims (6)

An evaporator for evaporating the working medium by heat-exchanging the gaseous heating medium supplied from the outside with the working medium;
A preheater for heating the working medium by exchanging heat between the heating medium flowing out of the evaporator and the working medium before flowing into the evaporator,
An energy recovery unit for recovering the expansion energy of the working medium flowing out of the evaporator and sending the working medium to the preheater,
When the supercooling degree of the heating medium flowing into the preheater is not greater than 0 degrees, the heating medium is prevented from flowing into the preheater. When the supercooling degree of the heating medium flowing into the preheater is greater than 0 degrees And a control unit for performing an operation of introducing the heating medium into the preheater. The method according to claim 1,
Wherein the control unit causes the heating medium to flow into the preheater when the supercooling degree of the heating medium flowing into the preheater is greater than 0 degree and the supercooling degree of the heating medium flowing out of the evaporator is not less than a specific lower limit value, And the supercooling degree of the heating medium flowing into the evaporator is less than the lower limit value even if the supercooling degree of the heating medium flowing into the evaporator is not greater than 0 degrees or the supercooling degree is greater than 0 degrees, The heat energy recovering device performing the prohibiting operation. 3. The method according to claim 1 or 2,
Wherein the control unit causes the heating medium to flow into the preheater when the supercooling degree of the heating medium flowing into the preheater is greater than 0 degree and the supercooling degree of the heating medium flowing out of the evaporator is not more than a specific upper limit value, When the supercooling degree of the heating medium flowing into the evaporator is not greater than 0 degrees or the supercooling degree of the heating medium flowing out from the evaporator is larger than 0, the heating medium is introduced into the preheater And discharging the heat energy to the outside without any work. 3. The method according to claim 1 or 2,
Wherein the control unit causes the heating medium to flow into the preheater when the supercooling degree of the heating medium flowing into the preheater is greater than 0 degrees and the supercooling degree of the working medium flowing into the evaporator is greater than 0 degrees, When the supercooling degree of the heating medium flowing into the preheater is not greater than 0 degrees or if the supercooling degree of the working medium flowing into the evaporator is not larger than 0 degrees even if the supercooling degree is larger than 0 degree, The heat energy recovery device comprising: 3. The method according to claim 1 or 2,
Wherein the control unit performs an operation of discharging the heating medium to the outside without introducing the heating medium into the preheater when a predetermined stop condition is established. 3. The method according to claim 1 or 2,
Further comprising a connection flow path connecting the preheater and the evaporator,
Wherein the connection passage has a shape extending in a straight line.

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